The actress, who was kept in the dark about her character's surprising storyline, reveals to THR what Charles has in mind for the Liars: "It won't be pretty."

[Warning: This story contains spoilers from the season-five finale of ABC Family's Pretty Little Liars.]

Pretty Little Liars' sixth season will be particularly eventful for a certain Rosewood resident.

Fans of the ABC Family drama were in for a stunning twist during Tuesday's season-five finale, as it was revealed that Mona (Janel Parrish) wasn't actually dead but had been held captive by the always-devious "A," who goes by the name of Charles DiLaurentis.

The show's viewers weren't the only ones taken aback by Mona's resurrection, as Parrish tells The Hollywood Reporter she had no idea until just before shooting the finale that her character was still among the living.

Parrish also talks about how the mysterious Charles will be punishing the Liars, where Mona and Mike's (Cody Christian) relationship is headed and what Mona will be doing after the series' upcoming time jump.

Did you initially believe that Mona was actually dead?

I did because [creator and executive producer] Marlene [King] called me and told me I was dead, and she's sneaky! But then she called me right before we filmed the finale and told me that I was, in fact, alive. And I was very happy about that because, while I was still on the show as "the flashback girl," now I have a lot more scenes, and I get to be on set and working with people that I love.

What was it like to film the finale?

It was intense! Definitely intense. I was actually doing Dancing With the Stars at the time, so I was exhausted, and we were trying to find time to rehearse. So it was pretty crazy, but once you're on set and you're in that world, you just get so into it. It was so much fun. I love action-packed days where I get to run around and do stunts and be scared. I've always wanted to do a horror film, so I feel like all of my dreams came true during the finale. We got to kind of pretend we were in a horror film. (Laughs.)

Basically, the girls will be trying to escape. They will be punished for trying to get away from Charles, and it won't be pretty. I know eventually that they will get out [of the dollhouse] but with some serious emotional scars. The season will be pretty dark. Throughout the season, we'll be finding out more about what happened to these girls while they were in the dollhouse and who exactly is Charles and why is he doing this.

Will Mona and Mike continue their romance?

I hope so! I definitely hope so. They had a very sweet relationship, and I really enjoy working with Cody. I think he broke all of our hearts in that scene where he thought Mona was truly dead, so I really hope that they can find their way back to each other.

How will Mona interact with Alison moving forward?

I really hope that they can find a way to form an alliance, since they both have wronged each other in the past. I think that Mona is humbled now in knowing that Alison had nothing to do with her disappearance, and I really hope that they can find a way to work together because they ultimately have a common enemy.

I think my reaction was the same as everybody else, like, "Who the hell is Charles?" And Marlene is a genius — she is so good at keeping things from people because she has to. She has to run a mystery of a show, so she can't tell everybody the story, so she hasn't told us much. I'm very excited to find out who this person is.

The show is planning a time jump in the second half of season six. What's in store for Mona at that point?

I actually don't know anything about that — I kind of just heard about that idea today. I hope that Mona does go off and go to college. The dark, twisted part of me hopes that "A" is still around torturing [everyone] because that's why we watch the show.

What has the fan response been to Mona's return?

It's been very mixed, but for the most part, I think that people are happy that I'm alive, which makes me very happy. I feel very special and very loved. Mostly, people are just like, "What the hell?" We took them on a crazy, wild ride, so I think everybody just wants answers, and they will definitely get them for season six.

Pretty Little Liars returns for its sixth season in June on ABC Family. Let us know your theories about Charles in the comments!